The rapid depletion of our known fossil fuel reserves is inversely proportional to the cost of fuel for the internal combustion engine. Accordingly, our affluent society is already faced with an exorbitant fuel price structure which recently was abruptly thrust upon the world. This escalation in hydrocarbon cost has created a frantic activity toward alternate sources of energy and the more efficient use of our remaining fuel supply. Historically, it is world-wide dilemma of this sort that creates the necessity for change and improvement.
The practical internal combustion engine is a relatively recent innovation. The internal combustion engine is notoriously inefficient in its ability to convert fuel into mechanical energy. The most prolific user of fossil fuel is the highly inefficient internal combustion engine which was originated and developed during an abundance of hydrocarbon fuel which heretofore was available at affordable prices; and consequently the gratifying results produced by the internal combustion engine, along with low fuel cost, negated any effort towards achieving significient increased fuel efficiency. Most internal combustion engines manufactured today use the old basic concept of producing rotatory mechanical movement from reciprocatory motion, as the result of the expansion of a combusted air and fuel mixture contained within a closed cylinder. An inherent drawback of this ancient design is that only a small portion of power available from the combustion process is converted into mechanical energy. Recently industry has invested significant effort and money towards improving the efficiency of these engines, however these efforts are primarily directed toward improving the efficiency of the ancilliary components of the engine; that is, fuel flow and combustion mixture, ignition, flame propagation, valve timing, and the like. Many internal combustion engine experts consider it impossible to achieve an efficiency significantly above the present 30 percent level, which is accomplished only when operating the engine under optimum conditions. Accordingly, regardless of the improvements effected into the ancilliary components of a crankshaft type engine, a further significant increase in efficiency cannot be achieved with this present internal combustion engine.
The internal combustion process appears to be the most logical manner of producing mechanical energy from hydrocarbons, and this has been amply demonstrated by the crankshaft type internal combustion engine presently in use. Therefore, it appears that in order to significantly increase the efficiency of a combustion engine, further utilization of the available energy from each power stroke of a combustion process must be converted into mechanical energy, rather than wasted in the form of exhaust gases, friction, and waste heat. An engine which achieves this desirable result is the subject of the present invention.
A significant increase in efficiency from the combustion process occurs by precisely metering the air and fuel to provide a stoichiometric combustion mixture, thereby providing the maximum available temperatures, because the expansive force against the engine piston is directly proportional to the temperature of the combustion gases. Accordingly, the present invention includes means by which a precisely controlled fuel to air ratio is achieved.
Theoretically, the available work resulting from the placement of an optimum air-fuel mixture of known quantity within a cylinder of a given size, having a piston properly positioned to commence the power stroke, can be calculated to ascertain the maximum energy available from the piston at all positions of the power stroke. It is known that immediately after ignition of the combustion mixture, the maximum pressure is developed within the combustion chamber. As the piston continues to move, the expansion of the combustion gases provide a steadily decreasing force, or pressure differential, across the piston. Since this pressure differential is proportional to the combustion chamber pressure, and since the combustion chamber pressure is steadily declined as the piston is stroked, the energy available from harnessing the movable piston likewise declines as the piston approaches the end of the power stroke. Accordingly, it would appear advantageous to be able to extract the declining energy available from the piston by providing an energy accumulating opposing force of a correspondingly steadily declining nature which corresponds to the force generated by the moving piston, thereby capturing substantially all of the available energy from the process.
Mobile vehicles, such as the automobile, operate under an infinite number of speed and load conditions. Variation in speed or load requirements is accomplished by changing the internal combustion process proportional to power demand or desired performance, and not according to fuel efficiency. Slow speeds, or low power demands, is accomplished by placing a small fraction of the optimum fuel charge into each of the combustion chambers. Higher speed or greater load requirements is satisfied by allowing the combustion process to be carried out with a much greater than optimum fuel charge, and accordingly there are very few speeds or conditions of operation which represent an efficient utilization of available energy.
In a crankshaft type internal combustion engine, the resultant forces of the reciprocating piston is transmitted by the connecting rod into the rotating crankshaft at varying degrees of oblique angles in order that reciprocatory motion may be changed into rotary mechanical motion. The resultant forces are transmitted at an extreme mechanical disadvantage. Moreover, this configuration between the piston and the crankshaft precludes the provision of a corresponding, uniform, declining, energy receiving, opposing force referred to above.
Accordingly, the greatest impediment to implementing significant increase in the efficiency of the crankshaft type internal combustion engine lies between the thermal process and the mechanical process. Therefore, any significant improvement would appear to require that the internal combustion process be actuated intermediately in a manner to maintain a level of available power which always equals or more nearly matches the varying power demand. This entails separation or isolation of the combustion process from any direct mechanical connection in a power train. Accomplishment of this separation requires that a transfer medium be provided between the energy producing and the energy consuming portions of the system. Ideally, the transfer medium must be able to absorb substantially all of the energy developed by the combustion process, regardless of its intensity or rate. Accordingly, the medium must provide a means of extracting energy from the moving piston, whereby each power stroke is opposed by a force which closely approximates the available power during the engine power stroke. The transferred medium can be either electric or hydraulic; and, since anything, or most anything that is accomplished hydraulically can be duplicated electrically, the present disclosure revolves about a specific hydraulic principle of operation with it being understood that those skilled in the art can also relate the teachings herein to electrical principle of operation.
The above concept enables a hydraulic oil accumulator to be used as the transfer medium. The accumulator receives varying quantities of energy, and stores the excess energy, so that there is no unused or wasted energy from the combustion process.